1. Field of the Invention
The present invention relates to an electronic apparatus provided with a case for housing an electronic circuit substrate on which heat generating electronic components are mounted, for example.
2. Description of the Related Art
Along with the development of techniques of miniaturization and large-scale integration of electronic components, the miniaturization of electronic apparatuses provided with electronic circuit substrates, typically optical transceivers, has developed rapidly recently. Problems with increased heat generation density due to the miniaturization of the electronic apparatuses provided with electronic circuit substrates has begun to be recognized. In addition, the heat distribution within an electronic apparatus provided with an electronic circuit substrate has a tendency to concentrate in specific locations due to the high integration of electronic components, and this trend can be predicted to become increasingly strong. In view of the further increase in the heat generation density and the concentration of the heat generation distribution in the future, there is a demand for the development of an electronic apparatus provided with an electronic circuit substrate and having superior heat dissipating characteristics.
Conventionally, a ceramic substrate having superior heat conduction characteristics and superior electrical characteristics is generally used for as a substrate material, and the entire rear surface of the substrate is contacts a case by using an adhesive or the like, for cases of dissipating heat from an electronic apparatus provided with an electronic circuit substrate in which the amount of heat generated increases, and the heat generation distribution becomes concentrated, as stated above.
For example, a structure like that shown in FIG. 13 may be used as a conventional electronic apparatus provided with an electronic circuit substrate. Reference numeral 1 in FIG. 13 denotes a heat generating component such as a heat generating electronic component, for example a power transistor. Reference numeral 2 denotes an electronic circuit substrate structured by a ceramic substrate, and the heat generating component 1 is mounted on the front surface of the electronic circuit substrate 2. Reference numeral 3 denotes a case for housing and protecting the electronic circuit substrate 2, and the top of the case 3 is open in order to place the electronic circuit substrate 2 into, and take the electronic circuit substrate 2 out of, the case 3. Reference numeral 4 denotes an adhesive for fixing the electronic circuit substrate to the case 3, and reference numeral 5 denotes a cover that covers the open portion of the case 3.
With the aforementioned structure of this first conventional example of an electronic apparatus provided with an electronic circuit substrate, heat generated by the first heat generating component 1 diffuses over the entire electronic circuit substrate 2, composed of the ceramic substrate having superior thermal conductivity characteristics, and the diffused heat is transferred to the case 3 via the adhesive 4. Heat transmitted to the case 3 then is dissipated to the atmosphere as the case 3 fulfills a role as a heat radiator.
In this case, heat generated by the heat generating component diffuses over the entire substrate in accordance with using the ceramic substrate having superior thermal conduction characteristics as the electronic circuit substrate 2. The diffused heat is dissipated to the case 3, provided with a heat radiator effect, from the entire rear surface of the electronic circuit substrate 2 contacting the case 3. Heat is therefore dissipated with good efficiency.
FIG. 14 is a schematic structure diagram showing a second conventional example of an electronic apparatus provided with an electronic circuit substrate, disclosed in JP 8-204070 A. A through hole 23 is wired for sending signals from a semiconductor element 21 within an electronic circuit substrate 22 on which the semiconductor element 21 is mounted. A flexible thermal conductor 24 or an adhesive adheres to a surface that is different from the surface on which the specific semiconductor element 21 is mounted on the electronic circuit substrate 22. A protruding portion 25 of a metal frame wall 26 contacts the thermal conductor 24.
In this case, much of the heat from the semiconductor element 21 is diffused widely into the frame wall 26 through the protruding portion 25. A high heat dissipating ability can be obtained with respect to the semiconductor element 21 by utilizing the large surface of the frame wall as a dissipating surface.
Further, a structure is shown in a third conventional example disclosed in JP 11-40742 A in which a lower surface of a module case contacts a metal portion formed on a mother board, and heat from the metal portion is transferred to a ground or to an electric power source layer within the mother board. Heat is dissipated, and dissipation fins on the module of the electronic circuit package are unnecessary.
However, with the electronic apparatus provided with an electronic circuit substrate, the first conventional example structured as stated above, a ceramic substrate must be used as the material of the electronic circuit substrate 2, and mounting must be performed so that the entire rear surface of the electronic circuit substrate contacts the case 3. A problem therefore develops in which the packaging density drops. In other words, a ceramic material having superior thermal conductivity characteristics is generally used as the substrate material because of the necessity to dissipate heat, as stated above, for cases in which the heat generating component 1 is mounted to a miniaturized electronic apparatus provided with an electronic circuit substrate, and mounting is performed so that the entire rear surface of the electronic circuit substrate 2 contacts the case 3. Normally, therefore, electrical/electronic components are not mounted to the rear surface of the electronic circuit substrate 2. Note that, even for cases in which the packaging density is given great weight and electrical/electronic components are mounted on the rear surface of the electronic circuit substrate 2, the ceramic substrate is attached floating above the case 3, and therefore it can be considered that the strength of the ceramic cannot withstand factors in its usage environment, such as vibration and shocks. Cracks and the like will be develop. With conventional examples, mounting of electrical/electronic components is limited to only one surface of the electronic circuit substrate 2, and therefore a problem exists in that the component packaging density is halved.
Further, a high component cost ceramic material must be used as the electronic circuit substrate 2 material, and therefore a problem exists in that the manufactured product cost increases.
Much of the heat from the semiconductor element 21 diffuses widely in the frame wall 26, through the thermal conductor 24 and the protruding portion 25, with the electronic apparatus of the second conventional example, and the heat dissipation capabilities with respect to the semiconductor element 21 increase. However, of the heat generated by the semiconductor element 21, that which is dissipated by thermal conduction is limited to a route in which it is dissipated to the outside from the through holes 23, the thermal conductor 24, the protruding portion 25, and the frame wall 26. For example, if the semiconductor element 21 is small, then a problem exists in that a region for the through holes 23 cannot be made large, and the heat dissipating capability of the semiconductor element 21 cannot be expected to increase.
Furthermore, the protruding portion 25 is formed such that it protrudes at a right angle into the inside of a portion of the frame wall 26. The protruding portion 25 consists of a level portion 25a and a vertical portion 25b. Of the heat generated by the semiconductor element 21, heat dissipated by thermal conduction passes through the vertical portion 25b. However, a problem exists in that the cross sectional surface area of the vertical portion 25b for heat to pass through has a large thermal resistance.
Further, the dimensions of the level portion 25a of the protruding portion 25 are larger than the dimensions of the semiconductor element 21, and therefore a problem exists in that the surface area for mounting electronic components to the rear surface of the electronic circuit substrate 22 becomes small.
With the third conventional example of the electronic apparatus, heat dissipation due to thermal conductivity of the heat of the electronic circuit package module is limited to a route in which it is emitted to the outside form the through holes, the ground or the electric power source layer, and the mother board. Similar to the second conventional example, the through hole region cannot be make large, and therefore a problem exists in that an increase in the thermal dissipation of the module cannot be expected.
The present invention aims to solve the above problems with the conventional art and the object of the present invention is to provide an electronic apparatus provided with an electronic circuit substrate which is inexpensive with high packaging density and superior heat dissipating characteristics and reliability.
In order to achieve the above objects, according to one aspect of the present invention there is provided an electronic apparatus provided with an electronic circuit substrate comprising:
an electronic circuit substrate comprising a resin circuit board formed with a wiring a pattern and a grounding pattern in an internal layer thereof a plurality of through holes provided directly below a portion where a non-encapsulated heat generating component is mounted and connected with the grounding pattern, and
a case for protectively housing the electronic circuit substrate provided with a heat dissipating protruding surface portion contacting an area where the through holes of a rear surface of the electronic circuit substrate are disposed, and being formed so as to ensure a space between the case and the rear surface of the electronic circuit substrate for enabling mounting of low heat generating electrical/electronic components.
According to another aspect of the present invention there is provided an electronic apparatus provided with an electronic circuit substrate comprising:
an electronic circuit substrate comprising a resin circuit board formed with a wiring pattern and a grounding pattern in an internal layer thereof, a plurality of through holes provided directly below a portion where a heat generating component is mounted and which are not connected to the grounding pattern, and opposing insulating grooves formed in a front and rear surface of the electronic circuit substrate so as to surround the heat generating component, and
a case for protectively housing the electronic circuit substrate provided with a heat dissipating protruding surface portion contacting an area where the through holes of the rear surface of the electronic circuit substrate are disposed, and being formed so as to ensure a space between the case and the rear surface of the electronic circuit substrate for enabling mounting of low heat generating electrical/electronic components.
According to the present invention there is provided an electronic apparatus provided with an electronic circuit substrate wherein:
a filler of a material with high thermal conductivity is filled in the plurality of through holes, and a heat dissipating grease intervenes at a contact portion between an area where the through holes of the electronic circuit substrate rear surface are disposed and the heat dissipating protruding surface portion of the case.
Moreover, in the present invention the heat generating component is an electrical/electronic component which generates a large amount of heat, such as a power transistor and the like, and the low heat generating electrical/electronic components are electrical/electronic components in which the amount of generated heat is smaller than in the heat generating component.
According to yet another aspect of the present invention there is provided an electronic apparatus comprising:
an electronic circuit substrate having mounted on a surface thereof a first non-encapsulated heat generating electronic component and a case for housing the electronic circuit substrate; wherein the electronic circuit substrate has a plurality of through holes disposed directly below the first non-encapsulated heat generating electronic component, and thermally connected to said first non-encapsulated heat generating electronic component; the first electronic circuit substrate has a grounding pattern thermally connected to the through holes; and wherein the case has a protruding portion disposed in contact with a rear surface portion of the electronic circuit substrate directly below the first non-encapsulated heat generating electronic component and thermally connected to the through holes.
According to yet another aspect of the present invention there is provided an electronic apparatus comprising:
an electronic circuit substrate having mounted on a surface thereof a first heat generating electronic component; and a case for housing the electronic circuit substrate; wherein the electronic circuit substrate has a plurality of through holes disposed directly below the first heat generating electronic component, and thermally connected to the first heat generating electronic component; the electronic circuit substrate has a plurality of grounding patterns of mutually different shapes thermally connected to the through holes; and wherein the case has a protruding portion disposed in contact with a rear surface portion of the electronic circuit substrate directly below said first heat generating electronic component and thermally connected to the through holes.
According to yet another aspect of the present invention there is provided an electronic apparatus comprising:
an electronic circuit substrate having mounted on a surface thereof a first heat generating electronic component and a case for housing the electronic circuit substrate; wherein the electronic circuit substrate has a plurality of through holes disposed directly below the first heat generating electronic component, and thermally connected to the first heat generating electronic component; the electronic circuit substrate has a grounding pattern thermally connected to the through holes; the case has a protruding portion disposed in contact with a rear surface portion of said electronic circuit substrate directly below the first heat generating electronic component and thermally connected to the through holes; the protruding portion having a prismoid shape composed of a level portion and an inclined portion; the through holes having positioned within the horizontal projection of the level portion of the protruding portion; and the first electronic component being formed to extend beyond the level portion.
According to yet another aspect of the present invention there is provided an electronic apparatus comprising:
an electronic circuit substrate having mounted on a surface thereof a first heat generating electronic component, a second electronic component and a case for housing the electronic circuit substrate; wherein the case has a protruding portion disposed in contact with a rear surface portion of the electronic circuit substrate directly below the first heat generating electronic component and thermally connected to the electronic circuit substrate; the protruding portion having a prismoid shape composed of a level portion and an inclined portion; and the second electronic component being mounted on a rear surface of the electronic circuit substrate, opposite the inclined portion.
According to yet another aspect of the present invention there is provided an electronic apparatus comprising:
an electronic circuit substrate having mounted on a surface thereof a first heat generating electronic component and a case for housing the electronic circuit substrate; wherein the electronic circuit substrate has a plurality of through holes disposed directly below the first heat generating electronic component, and thermally connected to the first heat generating electronic component; the electronic circuit substrate has a grounding pattern thermally connected to the through holes; the case has a protruding portion disposed in contact with a rear surface portion of the electronic circuit substrate directly below said first heat generating electronic component and thermally connected to the through holes; and wherein a heat dissipating grease is disposed in a continuous manner between the first electronic components and the electronic circuit substrate, within the through holes, and between the electronic circuit substrate and the protruding portion.
The electronic apparatus of the present invention is provided with an electronic circuit substrate and a support member for supporting the electronic circuit substrate, and a pin having a step, formed between the electronic circuit substrate and the support member. The stepped pin has a small diameter portion that is inserted from a rear surface of the electronic circuit substrate into a front surface, through an insertion hole formed on the electronic circuit substrate, and a large diameter portion that contacts the rear surface of the electronic circuit substrate. The electronic circuit substrate is fixed to the small diameter portion of the stepped pin by using solder.
In the electronic apparatus of the present invention, the stepped pin may have a caulking fixture portion opposite the small diameter portion for fixing the stepped pin after inserted into the insertion hole of the support member.
With the electronic apparatus of the present invention, electronic components may be mounted on both sides of the electronic circuit substrate by forming a space between the electronic circuit substrate and the supporting member by the large diameter portion of the stepped pin.
The electronic apparatus of the present invention is provided with the electronic circuit substrate, the case for housing the electronic circuit substrate, and optical semiconductor components fixed to the case, and the electronic circuit substrate and the optical semiconductor components are electrically connected by a film substrate.
The electronic apparatus of the present invention is mounted with a heat generating electronic component, and has: an electronic circuit substrate having a plurality of through holes, directly beneath the heat generating electronic component, which are thermally connected to the heat generating component; and a heat dissipating member which contacts a rear surface portion of the electronic circuit substrate directly below the heat generating electronic component and which is thermally connected to the through holes. The electronic circuit substrate has a groove or a slit formed between a signal pattern of the heat generating electronic component and the area where the plurality of through holes are formed.